1. Field of the Invention
The present invention relates to a brazing fixture for receiving an article to be brazed. The brazing fixture is especially adapted to receive a heat exchanger therein.
2. Discussion of the Related Art
Heater cores and certain other heat exchangers are manufactured by assembling tubes with fins thereon. A header plate is then attached to each end of the tubes and a tank is placed adjacent to each header plate. This assembly is then inserted into a furnace and the assembly is heated until it brazes together.
It was found that this procedure was not effective in obtaining proper brazing of all the components in the assembly. Specifically, the last outer fins on each side of the core and the side supports were not being properly brazed to the core and also the tanks were not being properly brazed to the header plates. To solve this problem, a steel band was placed around the core, including the side supports and a steel wire was placed around the core, including around the tanks. The configuration of the inlet and outlet tubes on the tanks usually prevented the use of a steel band around the tanks and thus a wire was used. The steel band was attached by a banding machine and required a separate work station prior to the brazing procedure. Likewise, the steel wire, was hand fed around each core and it was twisted tight by a spinner machine. This required another work station prior to the brazing procedure.
Following the brazing procedure, the bands and wires were cut off of each heater core and discarded. This resulted in a large amount of waste bands and wires.
Therefore, it can be seen that the above procedure included extra machines in the manufacturing procedure with additional time and expense associated with operating these machines and with removing the bands and wires after brazing.
Another problem that occurred was that even though the brazing procedure had been improved by the force exerted by the bands and wires, as the heater core heated up in the furnace, the bands and wires also heated up. As the bands and wires heated up, they expanded and they failed to maintain a constant pressure on the heater core. Thus some of the advantage of using the bands and wires was also lost.
Gersbacher (U.S. Pat. No. 3,995,805) discloses a brazing fixture for plate type heat exchangers which exerts a holding pressure that is evenly distributed and uniformly applied. A hand operated lever generates pressure which is transferred by a plurality of pressure applying members. This device does not disclose using the weight of the heat exchanger to apply force to another portion of the heat exchanger for firmly holding the assembly together.
Gersbacher (U.S. Pat. No. 4,128,235) discloses a brazing fixture for plate type heat exchangers wherein multiple plates, fin elements and appropriate spacers are stacked upon one another and are held so that the parts maintain an assembled relation during brazing. This device does not disclose using the weight of the heat exchanger to apply force to another portion of the heat exchanger for firmly holding the assembly together.
Gersbacher (U.S. Pat. No. 4,155,157) discloses a brazing fixture for plate type heat exchangers wherein the fixture includes part locators. The part locators position the parts during assembly or loading and remain attached during brazing. The locators are influenced to maintain an engagement with assembled parts but are able to yield in controlled directions under expansion resulting from the heat of brazing. This device does not disclose using the weight of the heat exchanger to apply force to another portion of the heat exchanger for firmly holding the assembly together.